Fishway structure



April 11, 1961 J. M. WARDLE FIsHwAY STRUCTURE 2 Sheets-Sheet 1 Filed001:. 20, 1958 INYENTOR /%M MKM-5%@ ATTORNEY April 11, 1961 J. M. WARDLE2,978,873

FISHWAY STRUCTURE:

Filed Oct. 20,'1958 2 Sheets-Sheet 2 fie BY @wg M@ ATT RNEY UnitedStates FISHWAY STRUCTURE James M. Wardle, Ottawa, Ontario, Canada,assignor to llortlwest Power Industries Limited, Ottawa, Ontario, ana aFiled Oct. 20, 1958, Ser. No. 768,139

s claims. (ci. 61-z1) This invention relatesto fishway structures.

The problem of providing means for permitting passage of fish such` assalmonover obstructions such as artificial dams in coastal rivers iswell recognized. The problem involves `the provision for passage ofvarious types or varieties of salmonupstream for spawning and for thereturn of the fngerlings downstream.

Fishway structures heretofore proposed usually suffer from thedisadvantages of complicated and expensive `construction, of awkward andcostly maintenanceand of failure to provide passage of fish to anadequate and satisfactory degree.

lt is an object of this invention to provide a shway stmcture which issubject to compactand convenient construction, which may be readilyinstalled in any desired location, and which is fully adequate in`ensuring passage :of fish. i i The invention contemplates the provisionof a fishway comprising a sh ladder having therein a multiplicity ofpools, said pools being disposed in successive order in a plurality ofconvolutions defining a helix, said convolutions being arranged onedirectly above the other, each said convolution having therein aplurality of pools, and each saidv pool having orifices communicatingwith adjacent pools.

The invention will be described with reference to the accompanyingdrawings, in which 7 reference to Figures 3 and 4.

Figure 1 is a plan view of a tishway installation in accordance with theinvention, f.

Figure 2 is a perspective view of the fishway installation shown inFigure .1,

Figure?, is a plan view of a fishway structure in accordj Figure 5 isaplanview of a modied form of iishway structure, and

: Figure s isa partial side elevationef the ashway structure shown inFigure 5,

Referring to Figures l and 2, 1 is a river having an artificial dam 2forming part of a power supply system which includes a power house 3 onone shore of the river adjacent the downstream side of the dam.

The fishway structure in accordance with the invention which is arrangedto'provide a dam by pass for the fish is generally indicated at 4. Itincludes a fish ladder 5 which, in the installation illustrated, islocated adjacent the shore of the river opposite to the power house 3.The ladder 5 has a fish entrance 6 at the bottom thereof and may beprovided with a pair of wing walls 7 leading to such entrance. A shbarrier 8 leading from the end of the outer wing wall across the rivermay be provided to guide the fish into the ladder. The ladder has a fishoutlet 9 adjacent the top communicating with an aqueduct 10, whichextends across the dam below the crest thereof. The aqueduct 10communicates with an inclined slope section 11 on the upstream side ofthe lice dam and extending upwardly towards the crest. The ladder 5 isadapted to provide a fish elevator of constant height and extendingthroughout the major portion of the difference in downstream andupstream water levels, whereas the inclined slope section 11 willaccommodate liuctuations in water levels inthe upstream head pond andprovide an outlet for the fish at any such varying level. Normally, suchfluctuations in water levels will not exceed 20 feet.

The fish ladder will now be described with particular It comprises amultiplicity of steps 12 arranged in a helix of generally rectangularconfiguration in cross section. A wall or baille 13 forms a continuationof the river of each step thereby to form an enclosurelfor a pool ofwater. A plurality (twelve as shown) of such pools are provided in eachconvolution of the helix as indicated in Figure 4. Pools 14 may be ofuniform symmetrical dimensions while corner pools 15 are necessarily ofirregular shape. One of such corner pools 15 has a laterally extendingportion 16 which constitutes a resting pool. Each pool communicates withadjoining pools through orifices 17. As shown, two such orifices areprovided in each baille 13 and they may be arranged in staggeredrelation with those in one wall of a pool adjacent the midsectionthereof and those in the other wall adjacent the sides thereof. Eachorifice is preferably located adjacent the bottom or oor of the poolsand is inclined to provide a convenient passage for fish from one poolto another. The angle of inclination may be of the order of 20. At theentrance end of each orifice, the pool floor may be slightly inclined asindicated at 18 and at the outlet end the pool ioor is preferablyprovided with a spoon-shaped depression 19.

The arrangement and dimensions of the pools, with resting poolsat fixedintervals, are such as to simulate the varying rates of swimming speedof fish. While such characteristics will vary widely and will depend tosome extent on the circumstances surrounding each particularinstallation, the following data is given as representative of a typicalinstallation:

Overall plan dimensions a rectangle x 120 feet, with a hollow centralarea 30 x 70 feet.

Number of pools in cach convolution a 12, pool No. 1 being directlyunder pool No. 13 in the next convolution.

Number of constructions 14.

Resting poolsevery 12th pool.

Enlarged size of resting poo1 20 x 35 feet.

Width of pool.` 25 feet.

Number of pouls 168,

Equivalent length `if extended horizontally 3,920 feet. Head, ordifference in Water level between pools 1.5 feet. Vertical distancebetween top of fioor of pool and door of pool i j j, j

Rate of climb l vertical in 15.5 horizontal.

Depth of water in pool a 7 feet.

Distance along center line for one convolution 28() feet.

Length of pools on center line--- 8 pools, 22% feet, 4

pools, 25 feel: per convolution.

Average assumed time for fish to. pass 10 hours. Maximum number of fishin structure at any one time 29,170.

Number of fish passing through structure daily 38,000.

The resting pools are arranged in vertical alignment for economy infoundations.

It will be understood that the iish ladder may be of square rather thanrectangular configuration but, in a narrow river valley, a rectangularconfiguration is believed preferable. v

`Overall structure:

The lish ladder and associated flumes may be constructed of wood,reinforced concrete or other suitable materials or combinations thereof.

It is proposed-that the direction of the helix for climbing fish wouldbe4 clockwise if the ladder is on the left hand side of the river andanti-clockwise if on the right hand side of the river.

The number of convolutions need not necessarily be a. completed numberbut rather may linish with a half spiral so that entrance and exit poolsare on opposite ends of the structure. It is of course desirable to makeconditions as easy as possible for ascending fish .to enter the fishladder. It has been heretofore proposed to release additional water inthe lower portion of the fishway in order that there may be a stratum ofdownstream water at every depth iri` the river below the darn. In thestructure described it would be easy to introduce additional attractionway in the lower section of the iish ladder during periods of high waterin the tail race.

The structure described is quite compact whereby electric lighting andphysical supervision are simplified. y

In the case of a concrete dam, the iishway might be built as a part ofthe dam structure with resulting economy in costs.

While a square or rectangular lish ladder structure permits ease ofconstruction of resting pools, the structure may be of circular type asshown in Figures 5 and 6. This `structure comprises two concentriccylindricalwalls and 21 Iand a multiplicity of spirally or helicallyarranged steps Z2 therebetween and extending from bottom to top of thestructure. Radially extending walls or baliies 23 form divisions betweenthe steps to produce a plurality of pools 24 in helically ascendingorder. A plurality of spaced iioors 25 in the central area withincylindrical wall 21 forms a plurality of resting pools 26, each of whichcommunicates with one pool 24 in each convolution through opening 27.The lower entrance to the ladder is indicated at 28 and the upperentrance at 29. Two orifices 30 in each bafiie 23 are provided forcornmunication between the pools.

While dimensions 'and characteristics of particular installations of thecircular type of fish ladder will vary widely, the following datarelating to a particular installation is given by way of example:

252 feet. 90.6 feet.

19.3. 12.95 feet.

eig it Rise per sp al Center line 'Velocity of water 0.7 feet per see.

Length V3 feet. inclined 20 to horizontal.

Water velocity 9.1 feet per sec.

Discharge 108 cu. feet per sec,

It will be observed that, in the case of the two examples given, therate of climb is of the order of 1:15.5.

1t is believed that the gradient should not be substantially steeperthan 1:14 and will generally be Vof the order' It is proposedto'introduce a substance into the water adjacent the entrance of thefish ladder such substance being adapted to increase the urge of thesalmon to go upstream to spawn.

I claim:

1. A tishway comprising a multiplicity of pool enclosures arranged inascending order in a helix, said helix comprising ajpl'urality ofvertically aligned uniform con volutions,"each said convolution havingtherein a plurality of said pool enclosures, each said pool enclosurehaving an'imperforaterbottorn wall, end walls common to adjoining onesvof said pool enclosures, and side walls joining said end Walls, saidside and end walls being contiguous with said bottom Wall, and wallsforming a resting pool extending laterally from and communicating withone of said pool enclosures in each said convolution, each said end wallhaving an orifice forming a lish passageway extending therethrough topermit passage of fish from one of said pool enclosures to another.

2. A fishway as delined in claim 1, said walls forming all of saidresting pools being vertically aligned.

3. A lishwayas .dened in claim 1, the gradient of said helix being notsubstantially steeper than 1:14.

isisV 4. A fishway `as defined in claim 1, each said orifice having aninlet adjoining the bottom wall of one of said pool enclosures and anoutlet adjoining the bottom wall of the adjoiningupper pool enclosure,said oritice being inclined upwardly from said inlet to said outlet,said bottom wall having a recess therein disposed below said ReferencesCited in the fileA of this patentV UNITED STATES PATENTS 1,718,181Province et a1. June V18, 1929 2,094,892 Hurst oer. 5, 1931 FOREIGNPATENTS 490,190 France Dec. 3, 1918

